JP6351281B2 - Gas barrier laminate - Google Patents

Description

  The present invention relates to a gas barrier laminate having excellent gas barrier properties even under high humidity and excellent adhesion without lowering laminate strength.

  Plastic films such as polyamide films are excellent in strength, transparency and moldability, and are therefore used in a wide range of applications as packaging materials. However, since these plastic films have a large gas permeability such as oxygen, when used for packaging general foods, retort processed foods, cosmetics, medical supplies, agricultural chemicals, etc., the oxygen that permeated the film during long-term storage. The contents may be altered by such gases. Therefore, the plastic film used for these packaging applications is required to have a gas barrier property, and in the packaging of foods containing moisture, the gas barrier property under high humidity is also required.

  As a method of imparting gas barrier properties to a plastic film, there is a method of laminating a gas barrier layer on the film, and as the gas barrier layer, it is possible to use a material composed of a polycarboxylic acid polymer, a polyalcohol polymer, and a metal compound. Are known.

For example, Patent Document 1 discloses a polymer layer containing a plastic substrate, a gas barrier layer (D), and a divalent or higher metal compound (E) as a method for producing a gas barrier laminate having a gas barrier property even under high humidity. A method for producing a gas barrier laminate (3) by heating the gas barrier laminate (1) in which (F) is laminated in the presence of water is described.
And it is described that a gas barrier layer (D) is formed from the gas barrier layer forming coating material (C) containing polyvinyl alcohol (A) and an ethylene-maleic acid copolymer (B).
Further, it is described that the polymer layer (F) containing the metal compound (E) having a valence of 2 or more is laminated on at least one surface of the gas barrier layer (D), and the plastic substrate, the gas barrier layer (D), It is described that it is laminated as an undercoat layer (F1) located between the layers.

However, in the method of Patent Document 1, after forming a gas barrier layer, pressure treatment using an autoclave is performed in water containing a metal compound, and it is difficult to carry out continuously, resulting in poor productivity. It was a thing.
In Patent Document 1, the undercoat layer is formed by applying and drying a solvent-based paint, and then the gas barrier layer is formed by applying and drying a water-based paint. Therefore, the method of Patent Document 1 has problems in terms of economy and productivity, such as requiring an explosion-proof facility for using a solvent-based paint, and requiring application several times.

The inventors of the present invention studied the simultaneous application of a solvent-based undercoat layer-forming paint and a water-based gas barrier layer-forming paint using a curtain coater, etc. Occasionally, the coating film became uneven, and the obtained laminate did not exhibit gas barrier properties.
In addition, instead of using a water-based paint for forming the undercoat layer, it may be applied simultaneously using a curtain coater or the like, or after applying and drying the water-based paint for forming the undercoat layer, the water-based paint for forming the gas barrier layer However, none of the obtained laminates exhibited gas barrier properties.

JP 2004-322626 A

  The object of the present invention is to provide a gas barrier laminate that solves the above problems, has excellent productivity and economy, has excellent gas barrier properties even under high humidity, and has excellent adhesion without lowering laminate strength. It is in.

As a result of intensive studies on the above problems, the present inventors have found that the plastic substrate (I) is a multilayer film, and at least one layer thereof contains a specific amount of a metal compound, and a gas barrier containing a polycarboxylic acid therein. It has been found that the laminate obtained by laminating the layer (II) has an excellent gas barrier property even under high humidity, and does not have a decrease in laminate strength and is excellent in adhesion, and has reached the present invention.
That is, the gist of the present invention is as follows.
(1) The plastic substrate (I) is a multilayer film comprising a metal-containing layer and a resin layer,
The metal-containing layer contains 0.1 to 10% by mass of a metal compound , and a thermoplastic resin mixed with the metal compound is melt extruded.
Ri gas barrier layer containing a polycarboxylic acid (II) the name is laminated on the plastic substrate (I),
The gas barrier layer and the metal-containing layer are in contact,
After hydrothermal treatment at 95 ° C. for 30 minutes, the oxygen permeability in an atmosphere at 20 ° C. and a relative humidity of 65% is 0.01 to 16 ml / (m ² · day · MPa) ,
A gas barrier laminate, wherein the plastic substrate (I) is stretched .
(2) The gas barrier laminate according to (1), wherein the thermoplastic resin constituting the plastic substrate (I) is a polyamide resin or a polyester resin.
(3) The gas barrier layered product according to any one of (1) and (2), wherein the gas barrier layer (II) contains a polyalcohol.
(4) The gas barrier laminate according to any one of (1) to (3), wherein the metal constituting the metal compound is one selected from magnesium, calcium, and zinc.
(5) The gas barrier laminate according to any one of (1) to (3), wherein the metal compound is magnesium oxide.
(6) On the gas barrier layer (II) of the gas barrier laminate according to any one of the above (1) to (5) , the laminate adhesive layer (III) and the heat seal layer (IV) are laminated in this order. A gas barrier laminate, wherein the laminate has a laminate strength (X) of 300 g / 15 mm or more.
(7) A packaging bag comprising the gas barrier laminate according to any one of (1) to (6) above.

According to the present invention, it is possible to provide a gas barrier laminate having excellent productivity and economy, excellent gas barrier properties even under high humidity, and excellent adhesion without lowering laminate strength.
That is, in the present invention, a plastic base material having a multilayer structure containing a metal compound can be produced simply by adding the metal compound to the raw material of at least one layer of the plastic base material and coextrusion. The step of laminating a layer containing a metal compound on a substrate by coating or laminating can be omitted. Therefore, a gas barrier laminate can be obtained with a smaller number of processes than before, and therefore, industrial merit is extremely large from the viewpoint of productivity and cost.

Hereinafter, the present invention will be described in detail.
The gas barrier laminate of the present invention is obtained by laminating a gas barrier layer (II) on a plastic substrate (I) having a multilayer structure, and at least one layer of the plastic substrate (I) contains a metal compound. It is necessary. The layer containing the metal compound is preferably adjacent to the gas barrier layer (II) in terms of gas barrier properties.

  The metal constituting the metal compound is not particularly limited, and monovalent metals such as lithium, sodium, potassium, rubidium, and cesium, and magnesium, calcium, zirconium, zinc, copper, cobalt, iron, nickel, aluminum, and the like. A bivalent or higher metal is mentioned. Among them, a metal having a high ionization tendency is preferable from the viewpoint of easy reaction with carboxylic acid, and a monovalent or divalent metal is preferable from the viewpoint of gas barrier properties. Specifically, lithium, sodium, potassium, magnesium, calcium, and zinc are preferable, and magnesium, calcium, and zinc are more preferable. The type of metal is not limited to one type, and may be two or more types.

  In the present invention, the metal compound is a compound containing the above metal, and examples of the compound include oxides, hydroxides, halides, inorganic salts such as carbonates, bicarbonates, phosphates, sulfates, Examples thereof include carboxylate such as acetate, formate, stearate, citrate, malate and maleate, and organic acid salt such as sulfonate, and is preferably an oxide or carbonate. . Moreover, you may use a metal simple substance as a metal compound.

  Among the above metal compounds, preferred examples include lithium carbonate, sodium hydrogen carbonate, magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium acetate, calcium oxide, calcium carbonate, calcium hydroxide, calcium chloride, calcium phosphate, calcium sulfate, acetic acid. Calcium, zinc acetate, zinc oxide, zinc carbonate can be mentioned, and from the viewpoint of gas barrier properties, magnesium salts such as magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium acetate, calcium carbonate, calcium acetate, zinc oxide, Divalent metal compounds such as zinc acetate are preferred. From the viewpoint of the transparency of the plastic substrate (I), monovalent compounds such as lithium carbonate and sodium hydrogen carbonate, magnesium oxide, magnesium carbonate, and magnesium hydroxide are preferred. Magnesium salts such as um are preferred. These may be used alone or in combination of two or more.

  The metal compound is preferably in a powder form, and the average particle diameter is not particularly limited, but is preferably 0.001 to 10.0 μm, more preferably 0.005 to 5.0 μm, and 0 0.01 to 2.0 μm is more preferable, and 0.05 to 1.0 μm is particularly preferable. Since the haze of the plastic substrate (I) can be reduced, the metal compound preferably has a smaller average particle diameter. However, a metal compound having an average particle size of less than 0.001 μm has a large surface area, so that it easily aggregates, and coarse aggregates are scattered in the film, which may deteriorate the mechanical properties of the substrate. On the other hand, the plastic base material (I) containing a metal compound having an average particle size exceeding 10.0 μm tends to be broken when the film is formed, and the productivity tends to decrease.

  A metal compound can improve dispersibility, weather resistance, wettability with a thermoplastic resin, heat resistance, transparency, and the like by performing surface treatment such as inorganic treatment or organic treatment. Examples of the inorganic treatment include alumina treatment, silica treatment, titania treatment, zirconia treatment, tin oxide treatment, antimony oxide treatment, and zinc oxide treatment. Examples of the organic treatment include treatment using a fatty acid compound, a polyol compound such as pentaerythritol and trimethylolpropane, an amine compound such as triethanolamine and trimethylolamine, a silicone compound such as a silicone resin and alkylchlorosilane. .

  The content of the metal compound in the plastic substrate (I) needs to be 0.1 to 10% by mass, and is preferably less than 5% by mass from the viewpoint of haze. When the content of the metal compound in at least one layer in the plastic substrate (I) is 0.1 to 10% by mass, the resulting gas barrier laminate has excellent interlayer adhesive strength in the plastic substrate. The laminate strength when a heat seal layer is laminated to obtain a laminate can be improved, and excellent gas barrier properties can be obtained. However, when the content of the metal compound in the plastic substrate (I) is less than 0.1% by mass, the cross-linked structure formed by reacting with the polycarboxylic acid in the gas barrier layer (II) is reduced and obtained. In the gas barrier laminate, the gas barrier property is lowered. On the other hand, when the metal content of at least one layer in the base material (I) exceeds 10% by mass, the interlayer adhesive strength in the plastic base material (I) is lowered. When it is made into a product, the laminate strength is lowered, and when it is made into a packaging bag, it is very difficult in terms of practicality.

  The method for incorporating the metal compound into the plastic substrate (I) is not particularly limited, and it can be blended at an arbitrary point in the production process. For example, a method of adding a metal compound when polymerizing the thermoplastic resin constituting the plastic substrate (I), a method of kneading the thermoplastic resin and the metal compound with an extruder, a high concentration of the metal compound Examples include a method (masterbatch method) in which a masterbatch kneaded and blended is manufactured and added to a thermoplastic resin for dilution. In the present invention, the master batch method is preferably employed.

  In the present invention, the thermoplastic resin constituting the plastic substrate (I) includes polyolefin resins such as polyethylene, polypropylene and ionomer, polyamide resins such as nylon 6, nylon 66, nylon 46, nylon MXD6 and nylon 9T, and polyethylene terephthalate. Polyester resins such as polyethylene isophthalate, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polylactic acid, vinyl chloride, polystyrene resin, polycarbonate resin, polyarylate resin, ethylene -Vinyl acetate copolymers, ethylene-vinyl alcohol copolymers or mixtures thereof. Among these thermoplastic resins, when a packaging bag is configured, polyamide resin is preferable because of excellent puncture strength and impact resistance, and polyester resin is preferable because of excellent heat resistance and economy. preferable.

  The thermoplastic resin, if necessary, within a range that does not adversely affect the performance of the plastic substrate (I), a thermal stabilizer, an antioxidant, a reinforcing material, a pigment, a deterioration inhibitor, a weathering agent, a flame retardant, You may add 1 type, or 2 or more types of various additives, such as a plasticizer, antiseptic | preservative, a ultraviolet absorber, an antistatic agent, and an antiblocking agent. In addition, inorganic particles other than metal compounds and organic lubricants may be added to the thermoplastic resin for the purpose of improving the slip property of the plastic substrate (I), and among them, silica may be added. preferable.

  The thickness of the plastic substrate (I) can be appropriately selected according to the mechanical strength required for the obtained gas barrier laminate. For reasons of mechanical strength and ease of handling, the thickness of the plastic substrate (I) is preferably 5 to 100 μm, and more preferably 10 to 30 μm. When the thickness of the plastic substrate (I) is less than 5 μm, sufficient mechanical strength cannot be obtained, and the piercing strength tends to deteriorate.

  The plastic substrate (I) needs to have a multilayer structure, and at least one layer thereof needs to contain 0.1 to 10% by mass of a metal compound. Hereinafter, a layer containing a metal compound in a multilayer film is referred to as “metal-containing layer (M)”, and a layer other than “metal-containing layer (M)” in the multilayer film is referred to as “resin layer (R)”. Sometimes.

With respect to the plastic substrate (I), the gas barrier laminate is obtained by contacting the gas barrier layer (II) with the metal-containing layer (M) of the plastic substrate (I), (R) / ( M) / (II), (M) / (R) / (M) / (II), (II) / (M) / (R) / (M) / (II) and the like. Since these structures are such that the gas barrier layer (II) and the metal-containing layer (M) are in contact with each other, the polycarboxylic acid in the gas barrier layer (II) and the metal compound in the metal-containing layer (M) are likely to react. Gas barrier properties can be obtained efficiently. Among these, the structure of (R) / (M) / (II) is preferable in consideration of equipment for manufacturing and operability.
Further, the gas barrier layer (II) and the resin layer (R) of the plastic substrate (I) are in contact with each other, (M) / (R) / (II) and (R) / (M) / (R) / (II) and (II) / (R) / (M) / (R) / (II). Among these, considering the equipment for manufacturing and operability, the configuration of (M) / (R) / (II) is preferable.

  The thickness constitution ratio of the metal-containing layer (M) and the resin layer (R) constituting the plastic substrate (I) is not particularly limited, and the total thickness (Mt) of the metal-containing layer (M) and the resin layer (R) ) Of the total thickness (Rt) ((Rt) / (Mt)) is preferably 1/1000 to 1000/1, and the thickness control of each layer is easy, so 1/100 to 100 / 1, more preferably 1/10 to 10/1.

  The above-mentioned additives may be added to the thermoplastic resin constituting the resin layer (R), and the resin layer (R) which is the outermost layer of the gas barrier laminate is made of silica for the purpose of improving the slip property. Etc. are preferably added.

  The gas barrier layer (II) constituting the gas barrier laminate of the present invention needs to contain a polycarboxylic acid. The polycarboxylic acid in the gas barrier layer (II) can exhibit gas barrier properties by reacting with the metal compound in the plastic substrate (I).

The polycarboxylic acid in the present invention is a compound or polymer having two or more carboxyl groups in the molecule, and these carboxyl groups may form an anhydride structure.
Specific examples of the polycarboxylic acid include 1,2,3,4-butanetetracarboxylic acid, polyacrylic acid, polymethacrylic acid, acrylic acid-methacrylic acid copolymer, acrylic acid-maleic acid copolymer, polymaleic acid Examples thereof include olefin-maleic acid copolymers such as ethylene-maleic acid copolymers, polysaccharides having a carboxyl group in the side chain such as alginic acid, polyamides containing carboxyl groups, and polyesters. The above polycarboxylic acids can be used alone or in combination of two or more.

  When the polycarboxylic acid is a polymer, the weight average molecular weight is preferably 1,000 to 1,000,000, more preferably 10,000 to 150,000, and more preferably 15,000 to 1,000,000. More preferably, it is 110,000. If the weight average molecular weight of the polycarboxylic acid is too low, the resulting gas barrier layer (II) becomes fragile. On the other hand, if the molecular weight is too high, the handling property is impaired, and in some cases, the gas barrier layer (II) described later may be used. The gas barrier layer (II) obtained by agglomeration in the coating liquid for forming may have a gas barrier property impaired.

In the present invention, among the above polycarboxylic acids, polyacrylic acid and olefin-maleic acid copolymer, particularly ethylene-maleic acid copolymer (hereinafter, sometimes abbreviated as EMA) are from the point of gas barrier property. Preferably used. EMA is obtained by polymerizing maleic anhydride and ethylene by a known method such as solution radical polymerization.
The maleic acid unit in the olefin-maleic acid copolymer tends to have a maleic anhydride structure in which the adjacent carboxyl group is dehydration-cyclized in a dry state, and opens to form a maleic acid structure when wet or in an aqueous solution. Therefore, in the present invention, unless otherwise specified, maleic acid units and maleic anhydride units are collectively referred to as maleic acid units.
The maleic acid unit in EMA is preferably 5 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, and most preferably 35 mol% or more. .
Further, the weight average molecular weight of EMA is preferably 1,000 to 1,000,000, more preferably 3,000 to 500,000, and further preferably 7,000 to 300,000. It is preferably 10,000 to 200,000.

In the present invention, the gas barrier layer (II) preferably contains a polyalcohol. By containing a polyalcohol, the polycarboxylic acid in the gas barrier layer (II) reacts with the polyalcohol in addition to reacting with the metal compound in the plastic substrate (I), thereby improving the gas barrier property. be able to.
Polyalcohol is a compound having two or more hydroxyl groups in the molecule, and low molecular weight compounds include sugar alcohols such as glycerin and pentaerythritol, monosaccharides such as glucose, disaccharides such as maltose, and oligosaccharides such as galactooligosaccharides. Examples of the polymer compound include polysaccharides such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and starch. The above polyalcohols can be used alone or in combination of two or more.
The saponification degree of polyvinyl alcohol or ethylene-vinyl alcohol copolymer is preferably 95 mol% or more, and more preferably 98 mol% or more. The average degree of polymerization is preferably 50 to 2,000, and more preferably 200 to 1,000.

  The polycarboxylic acid and the polyalcohol in the gas barrier layer (II) are preferably contained so that the molar ratio of OH group to COOH group (OH group / COOH group) is 0.01 to 20. It is more preferable to contain so that it may become 01-10, It is more preferable to contain so that it may become 0.02-5, It is most preferable to contain so that it may become 0.04-2.

  In the present invention, the gas barrier layer (II) preferably contains polyacrylamide, polymethacrylamide or polyamine. By containing these compounds, the polycarboxylic acid in the gas barrier layer (II) reacts with these compounds in addition to reacting with the metal compound in the plastic substrate (I), so that the gas barrier property is improved. Can be improved.

The polyamine has two or more amino groups selected from primary and secondary as amino groups in the molecule. Specific examples thereof include polyallylamine, polyvinylamine, branched polyethyleneimine. And polysaccharides having an amino group in the side chain such as linear polyethyleneimine, polylysine and chitosan, and polyamides having an amino group in the side chain such as polyarginine.
The weight average molecular weight of the polyamine is preferably 5,000 to 150,000. If the weight average molecular weight of the polyamine is too low, the resulting gas barrier layer (II) becomes fragile. On the other hand, if the molecular weight is too high, handling properties are impaired, and in some cases, a gas barrier layer (II) described later is formed. Therefore, the gas barrier layer (II) obtained by agglomeration in the coating solution may have a gas barrier property impaired.

  In the gas barrier layer (II), the mass ratio of polyamine to polycarboxylic acid (polyamine / polycarboxylic acid) is preferably 12.5 / 87.5 to 27.5 / 72.5. If the mass ratio of the polyamine is lower than this, the crosslinking of the carboxyl group of the polycarboxylic acid becomes insufficient. Conversely, if the mass ratio of the polyamine is higher than this, the crosslinking of the amino group of the polyamine becomes insufficient. However, the gas barrier laminate obtained may be inferior in gas barrier properties.

The gas barrier layer (II) in the present invention may contain a crosslinking agent. By containing a cross-linking agent, gas barrier properties can be enhanced.
The content of the crosslinking agent in the gas barrier layer (II) is preferably 0.1 to 30 parts by mass and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polycarboxylic acid.
Examples of the crosslinking agent include a compound having a self-crosslinking property and a compound having a plurality of functional groups that react with a carboxyl group in the molecule. When the gas barrier layer (II) contains a polyalcohol, it reacts with a hydroxyl group. A compound having a plurality of functional groups in the molecule may also be used. Preferable examples of the crosslinking agent include isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, zirconium salt compounds such as zirconium ammonium carbonate, metal alkoxides, and the like. These crosslinking agents may be used in combination.

  A metal alkoxide is a compound containing a metal to which an alkoxy group is bonded, and an alkyl group substituted with a functional group having reactivity with a halogen or a carboxyl group may be bonded instead of a part of the alkoxy group. . Here, the metal includes atoms such as Si, Al, Ti and Zr, the halogen includes chlorine, iodine, bromine and the like, and the functional group having reactivity with a carboxyl group is an epoxy group. , Amino groups, isocyanate groups, ureido groups and the like, and alkyl groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group and the like. Examples of such compounds include tetramethoxysilane, tetraethoxysilane, chlorotriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, Alkoxysilane compounds such as 3-aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, alkoxytitanium compounds such as tetraisopropoxytitanium and tetraethoxytitanium, alkoxy such as triisopropoxyaluminum Examples thereof include aluminum compounds and alkoxyzirconium compounds such as tetraisopropoxyzirconium.

  These metal alkoxides must be partially or wholly hydrolyzed, partially hydrolyzed or condensed, fully hydrolyzed and partially condensed, or a combination of these. You can also.

  When the above metal alkoxide and polycarboxylic acid are mixed, it may be difficult for both to react and to be applied. Therefore, it is preferable to form a hydrolysis condensate in advance before mixing. As a method for forming the hydrolysis-condensation product, a method used in a known sol-gel method can be applied.

In the gas barrier layer (II) in the present invention, a heat stabilizer, an antioxidant, a reinforcing material, a pigment, a deterioration preventing agent, a weather resistance, as long as the gas barrier property and the adhesion to the plastic substrate (I) are not significantly impaired. An agent, a flame retardant, a plasticizer, a release agent, a lubricant, an antiseptic, an antifoaming agent, a wetting agent, a viscosity modifier, and the like may be added.
Examples of heat stabilizers, antioxidants, and deterioration inhibitors include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. May be.
Examples of the reinforcing material include clay, talc, wollastonite, silica, alumina, calcium silicate, sodium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zeolite, montmorillonite, hydrotalcite, fluorine mica, Examples thereof include metal fibers, metal whiskers, ceramic whiskers, potassium titanate whiskers, boron nitride, graphite, glass fibers, carbon fibers, fullerenes (C60, C70, etc.), carbon nanotubes, and the like.

  In the present invention, the thickness of the gas barrier layer (II) laminated on the plastic substrate (I) is preferably thicker than 0.05 μm in order to sufficiently enhance the gas barrier property of the gas barrier laminate, which is economical. Therefore, it is preferable that the thickness is less than 5.0 μm.

The gas barrier layer (II) in the present invention can be formed by applying and drying a gas barrier layer (II) forming coating solution on the plastic substrate (I).
Since the coating liquid is preferably aqueous from the viewpoint of workability, the polycarboxylic acid, polyalcohol and polyamine constituting the coating liquid are preferably water-soluble or water-dispersible, and water-soluble. It is more preferable that

  In the present invention, when an aqueous coating solution is prepared by mixing a polycarboxylic acid and a polyalcohol, it is preferable to add 0.1 to 20 equivalent% of an alkali compound with respect to the carboxyl group of the polycarboxylic acid. . Since polycarboxylic acid has high hydrophilicity when the content of carboxyl group is large, it can be made into an aqueous solution without adding an alkali compound. However, the gas barrier property of the obtained gas barrier laminate can be remarkably improved by adding an appropriate amount of an alkali compound. The alkali compound only needs to be capable of neutralizing the carboxyl group of the polycarboxylic acid, and the addition amount thereof is preferably 0.1 to 20 mol% with respect to the carboxyl group of the polycarboxylic acid.

  The coating liquid can be prepared by a known method using a melting pot equipped with a stirrer. For example, a polycarboxylic acid and a polyalcohol are separately made into aqueous solutions and mixed before coating. The method is preferred. At this time, if the alkali compound is added to the aqueous solution of the polycarboxylic acid, the stability of the aqueous solution can be improved.

  Moreover, in this invention, when mixing polycarboxylic acid and polyamine and preparing an aqueous coating liquid, in order to suppress gelatinization, it is preferable to add a base to polycarboxylic acid. The base may be any as long as it does not inhibit the gas barrier properties of the resulting gas barrier laminate, and examples thereof include inorganic substances such as sodium hydroxide and calcium hydroxide, and organic substances such as ammonia, methylamine, diethanolamine, and the like. Ammonia is preferable because it is easily volatilized by heat treatment. The addition amount of the base is preferably 0.6 equivalents or more, more preferably 0.7 equivalents or more, and more preferably 0.8 equivalents or more based on the carboxyl group of the polycarboxylic acid. preferable. If the amount of the base added is small, the coating solution may gel during coating, and it may be difficult to form the gas barrier layer (II) on the plastic substrate (I).

  The method for applying the coating liquid for forming the gas barrier layer (II) to the plastic substrate (I) is not particularly limited, and is an air knife coater, kiss roll coater, metering bar coater, gravure roll coater, reverse roll coater, dip coater. , Die coater, etc., or a combination of these can be used.

After applying the coating liquid for forming the gas barrier layer (II) to the plastic substrate (I), heat treatment may be performed immediately to form a dry film and heat treatment at the same time. Heat treatment may be performed after moisture or the like is evaporated by spraying or infrared irradiation to form a dry film. It is preferable to perform the heat treatment immediately after coating unless there is a particular problem with the physical properties such as the gas barrier layer (II) and gas barrier properties.
It does not specifically limit as a heat processing method, The method of heat-processing in dry atmosphere, such as oven, is mentioned. Considering shortening of the process, it is preferable to stretch the plastic substrate (I) after applying the gas barrier layer (II) forming coating solution.
In any of the above cases, the plastic substrate (I) on which the gas barrier layer (II) is formed is preferably subjected to a heat treatment for 5 minutes or less in a heated atmosphere of 100 ° C. or higher.

When the gas barrier layer (II) contains a polycarboxylic acid and a polyalcohol, it can be affected by the ratio, presence / absence of an additive component, the content thereof, and the like. The heat treatment temperature cannot be generally specified, but is preferably 100 to 300 ° C, more preferably 120 to 250 ° C, further preferably 140 to 240 ° C, and 160 to 220 ° C. It is particularly preferred. If the heat treatment temperature is too low, the cross-linking reaction between the polycarboxylic acid and the polyalcohol cannot sufficiently proceed, and it may be difficult to obtain a laminate having sufficient gas barrier properties, while it is too high. In addition, the gas barrier layer (II) and the like may become brittle.
The heat treatment time is preferably 5 minutes or less, more preferably from 1 second to 5 minutes, further preferably from 3 seconds to 2 minutes, and particularly preferably from 5 seconds to 1 minute. . If the heat treatment time is too short, the crosslinking reaction cannot proceed sufficiently, and it becomes difficult to obtain a laminate having gas barrier properties. On the other hand, if it is too long, productivity decreases.

  The coating liquid for forming the gas barrier layer (II) applied to the plastic substrate (I) is irradiated with high energy rays such as ultraviolet rays, X-rays, and electron beams as necessary before and after the drying. May be. In such a case, a component that is crosslinked or polymerized by irradiation with high energy rays may be blended.

[Laminate]
The gas barrier laminate of the present invention is laminated directly on the gas barrier layer (II) or via the printing ink layer, and the laminate adhesive layer (III) is further laminated on the heat seal layer (IV) in this order, A laminate in which (I) / (II) / printing ink layer / (III) / (IV) or (I) / (II) / (III) / (IV) is laminated in this order can be formed. Furthermore, a resin layer may be formed on the gas barrier layer (II) for protecting the gas barrier layer (II) and preventing blocking. In some cases, a functional layer such as a primer layer or an antistatic layer may be formed between the gas barrier laminate and the laminate adhesive layer (III). In order to improve the adhesion between the gas barrier laminate and the laminate adhesive layer (III), a surface treatment such as corona treatment or ozone treatment may be performed.

[Laminate adhesive layer (III)]
As the coating agent used when forming the laminate adhesive layer (III), known coating agents are used. Examples of the coating agent include isocyanate, polyurethane, polyester, polyethyleneimine, polybutadiene, polyolefin, and alkyl titanate. Among these, in consideration of effects such as adhesion, heat resistance, and water resistance, an isocyanate-based, polyurethane-based, or polyester-based coating agent is preferable, and a mixture of one or more of isocyanate compounds, polyurethanes, and urethane prepolymers. And a reaction product, a mixture of one or more of polyester, polyol and polyether with isocyanate and a reaction product, or a solution or dispersion thereof. The thickness of the laminate adhesive layer (III) is preferably at least 0.1 μm in order to sufficiently enhance the adhesion with the heat seal layer. The method for applying the laminate adhesive layer (III) to the gas barrier laminate is not particularly limited, and usual methods such as gravure roll coating, reverse roll coating, wire bar coating, and air knife coating can be used.

[Heat seal layer (IV)]
The heat seal layer (IV) is provided as a heat adhesive layer when forming a bag-like packaging bag or the like, and a material capable of heat seal, high frequency seal or the like is used. The resin used as the heat seal layer (IV) is low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, polyethylene / polypropylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin. , Ethylene-acrylic acid / methacrylic acid copolymer, ethylene-acrylic acid / methacrylic acid ester copolymer, polyvinyl acetate resin, and the like, polyethylene, polypropylene, polyethylene / polyethylene Polyolefin resins such as polypropylene copolymers are preferred. These resins may be used alone, or may be copolymerized or melt-mixed with other resins, or may be further acid-modified.
As a method of forming the heat seal layer (IV) on the gas barrier laminate, a method of laminating a film or sheet made of a heat seal resin on the gas barrier laminate via the above-mentioned laminate adhesive layer (III) And a method of extrusion laminating the heat seal layer (IV) to the gas barrier laminate. In the former method, the film or sheet made of the heat-seal resin may be in an unstretched state or a low-magnification stretched state, but is practically preferably in an unstretched state.
Although the thickness of heat seal layer (IV) is not specifically limited, It is preferable that it is 20-100 micrometers, and it is more preferable that it is 40-70 micrometers.

[Printing ink layer]
Addition of various pigments, extenders, plasticizers, desiccants, stabilizers, etc. to conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, rubber and vinyl chloride It is a character, a pattern, etc. formed with the ink to which an agent etc. are added. As a method for forming the printing ink layer, for example, a known printing method such as an offset printing method, a gravure printing method, a silk screen printing method, or a known coating method such as roll coating, knife edge coating, or gravure coating may be used. it can.

Since the gas barrier laminate of the present invention has the above-described configuration, it has excellent gas barrier properties. The gas barrier laminate that has been subjected to hydrothermal treatment at 95 ° C. for 30 minutes has an atmosphere of 20 ° C. and a relative humidity of 65%. the in measured oxygen ^{permeability, 300ml / (m 2 · day} · MPa) can be less, the oxygen permeability is preferably ^{0.01~300ml / (m 2 · day ·} MPa), more preferably 0.01～200Ml ^/ a (m 2 · day · MPa) , more preferably a ^{0.01~100ml / (m 2 · day ·} MPa).

  The gas barrier laminate of the present invention preferably has a tensile strength of 150 MPa or more, and more preferably 180 MPa or more. If the tensile strength is less than 150 MPa, the mechanical strength is not sufficient, and the piercing strength tends to decrease. In addition, the tensile elongation is preferably 60% or more, and more preferably 80% or more, from the same viewpoint as the tensile strength.

The pinhole resistance of the gas barrier laminate of the present invention is preferably 100 or less, more preferably 20 or less, in the 500 times repeated bending fatigue test at 5 ° C. preferable.
Specifically, the pinhole resistance is Fed. Shown in MIL-B-131F. Test Method Std. In accordance with Method 2017 of 101C, a sample of 12 inches × 8 inches is gripped in a cylindrical shape with a diameter of 3.5 inches, with an initial gripping distance of 7 inches and a gripping distance of 1 inch at maximum bending, a so-called gel bot tester (manufactured by Rigaku Corporation) The number of pinholes generated after being bent 500 times at 5 ° C. was measured and evaluated.

  The transparency of the gas barrier laminate of the present invention is preferably 70% or less of haze, more preferably 50% or less, further preferably 30% or less, and 15% or less. Particularly preferred is 10% or less. However, this is not the case because transparency may not be required depending on the application.

The gas barrier laminate of the present invention can be produced by the following method.
The plastic substrate (I) is obtained by, for example, heating and melting a thermoplastic resin mixed with a metal compound in the extruder A, and heating and melting the thermoplastic resin in the extruder B. For example, a film having a two-layer structure of a metal-containing layer (M) / resin layer (R) is extruded from a T die, and is rotated by a known casting method such as an air knife casting method or an electrostatic application casting method. By cooling and solidifying on a drum, an unstretched plastic substrate (I) film can be obtained.
By including the metal compound in the plastic substrate (I) by such a method, the step of conventionally laminating a layer containing the metal compound on the substrate by coating or laminating can be omitted.
The gas barrier layer (II) forming coating liquid is applied to the resulting multilayer unstretched film by the above-described method to form the gas barrier layer (II), and the longitudinal direction is measured with a tenter simultaneous biaxial stretching machine. By performing simultaneous biaxial stretching in the (MD) and transverse directions (TD), a gas barrier laminate that has been simultaneously biaxially stretched can be obtained.
Further, after stretching the obtained unstretched film in the machine direction (MD), the gas barrier layer (II) forming coating liquid is applied by the above-described method to form the gas barrier layer (II), and then the transverse direction (TD) ) To obtain a gas barrier laminate that is successively biaxially stretched.
If the unstretched film is oriented, the stretchability may be lowered in a later step. Therefore, it is preferable that the unstretched film is substantially amorphous and non-oriented.

When using a polyamide resin as the thermoplastic resin, transfer the unstretched film to a water tank whose temperature is adjusted so as not to exceed 80 ° C., and subject it to a water immersion treatment within 5 minutes and a moisture absorption treatment of 0.5 to 15%. Is preferred.
In addition, the stretching ratio of the film is preferably 1.5 times or more in the case of uniaxial stretching, and also in the case of longitudinal and lateral biaxial stretching, it is preferably 1.5 times or more in the vertical and horizontal directions. Usually, it is preferably 3 times or more, more preferably 6 to 20 times, and even more preferably 6.5 to 13 times. When the draw ratio is within this range, a gas barrier laminate having excellent mechanical properties can be obtained.
The film that has undergone the stretching process is heat-set at a temperature of 150 to 300 ° C. in the tenter where the stretching process has been performed, and in the range of 0 to 10%, preferably 2 to 6% as necessary, in the machine direction and A lateral relaxation treatment is performed. In order to reduce the heat shrinkage rate, it is desirable not only to optimize the temperature and time of the heat setting time, but also to perform the heat relaxation process at a temperature lower than the maximum temperature of the heat setting process.

  The stretching method is not particularly limited, but it is preferable to use a simultaneous biaxial stretching method. The simultaneous biaxial stretching method can generally have practical characteristics such as mechanical characteristics, optical characteristics, thermal dimensional stability, and pinhole resistance. In addition, in the sequential biaxial stretching method in which the transverse stretching is performed after the longitudinal stretching, the orientation crystallization of the film proceeds during the longitudinal stretching, and the stretchability of the thermoplastic resin during the transverse stretching is reduced, thereby blending the metal compound. When the amount is large, the breaking frequency of the film tends to increase. For this reason, in this invention, it is preferable to perform a water absorption process and to take the simultaneous biaxial stretching method.

  The gas barrier laminate of the present invention can be treated in a humidified atmosphere after producing the laminate for the purpose of enhancing gas barrier properties. By the humidification treatment, the action of the metal compound of the plastic substrate (I) and the polycarboxylic acid of the gas barrier layer (II) can be further promoted. In such humidification treatment, the laminate may be left in an atmosphere of high temperature and high humidity, or the laminate may be directly contacted with high temperature water. Humidification conditions vary depending on various purposes, but when left in an atmosphere of high temperature and high humidity, a temperature of 30 to 130 ° C. and a relative humidity of 50 to 100% are preferable. Also when making it contact with high temperature water, the temperature of about 30-130 degreeC (100 degreeC or more is under pressure) is preferable. The humidifying treatment time varies depending on the treatment conditions, but generally a range of several seconds to several hundred hours is selected.

  The gas barrier laminate of the present invention may be subjected to surface treatment such as corona discharge treatment, if necessary.

  When the laminate is formed by laminating the laminate adhesive layer (III) and the heat seal layer (IV) in this order directly on the gas barrier layer (II) of the gas barrier laminate of the present invention or via a printing ink layer, The laminate strength (X) of the laminate is preferably 300 g / 15 mm or more, and more preferably 400 g / 15 mm or more. When the laminate strength is less than 300 g / 15 mm, it is not preferable because a bag is formed from the laminate, the contents are filled and sealed, and a broken bag or unsuccessful opening is likely to occur.

  The packaging bag using the gas barrier laminate of the present invention includes, for example, food and drink, fruit, juice, drinking water, liquor, cooked food, marine product, frozen food, meat product, boiled food, rice cake, liquid juice. It is possible to fill and package contents such as various foods and beverages such as coffee, seasonings, etc., liquid detergents, cosmetics, and chemical products.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

1. Measurement Method (1) Average Particle Size A cumulative percent value of 50% in a particle size distribution (volume distribution) curve measured with a laser particle size analyzer “Microtrac HRA” (manufactured by Nikkiso Co., Ltd.) was determined. A sample for measuring the average particle diameter was prepared by adding 50 g of IPA to 0.5 g of the metal compound and performing ultrasonic dispersion treatment for 3 minutes.

(2) Thickness of each layer The obtained gas barrier laminate is allowed to stand for 2 hours or more in an environment of 23 ° C. and 50% RH, and then the cross section of the film is observed with a scanning electron microscope (SEM) to measure the thickness of each layer. did.

(3) Oxygen permeability After the obtained gas barrier laminate was hydrothermally treated at 95 ° C. for 30 minutes, it was left in an environment of 23 ° C. and 50% RH for 2 hours or more, and oxygen produced by Mocon Co. Using a barrier measuring device (OX-TRAN 2/20), the oxygen permeability was measured in an atmosphere at a temperature of 20 ° C. and a relative humidity of 65%. The unit is ml / (m ² · day · MPa).

(4) Laminate strength A test piece having a length of 100 mm × width of 15 mm was prepared from the obtained laminate, and a peel rate of 300 mm / min at a temperature of 23 ° C. and a relative humidity of 50% by a T-type peel test method. The laminate strength (X) was measured.

(5) Peeling interface For the peeling interface at the time of measurement of laminate strength (X), the test piece after measurement is left in an environment of 23 ° C. and 50% RH for 2 hours or more, and then by a scanning electron microscope (SEM). The film cross-section was observed, and the peeling interface was identified from the thickness of the peeling part. The peeling interface is the interface between the gas barrier layer (II) and the laminate adhesive layer (III) (represented as “II / III”) or the interface between the gas barrier layer (II) and the printing ink layer (represented as “II / ink”). In this case, it means that no peeling occurs between the metal-containing layer (M) and the resin layer (R) constituting the plastic substrate layer (I), which is a preferable peeling state.

2. Raw materials The raw materials used in the following examples and comparative examples are as follows.
(1) Thermoplastic resin for construction of plastic substrate (I) PA6: Nylon 6 resin (A1030BRF manufactured by Unitika Ltd., relative viscosity 3.0)
PET: Polyethylene terephthalate resin (UT-CBR intrinsic viscosity 0.62 manufactured by Unitika)

(2) Metal compound for construction of plastic substrate (I) MgO: Magnesium oxide (Puremag FNM-G average particle size 0.4 μm, manufactured by Tateho Chemical Co., Ltd.)
MgO-2: Magnesium oxide (Tateho Chemical Industries, Ltd. TATEHOMAG # H-10 average particle size 4.9 μm)
MgCO ₃ : Magnesium carbonate (manufactured by Kamishima Chemical Industry Co., Ltd. MSS average particle size 1.2 μm)
-CaCO ₃ : Calcium carbonate (Vigot 15 average particle size 0.5 μm, manufactured by Shiroishi Kogyo Co., Ltd.)
ZnO: Zinc oxide (FINEX-50 average particle size 0.02 μm, manufactured by Sakai Chemical Industry Co., Ltd.)

(3) Plastic compound (I) Metal compound master chip / master chip 1 for construction
It was prepared by kneading 85 parts by mass of PET and 15 parts by mass of MgO.
・ Master chip 2
It was prepared by kneading 85 masses of PA6 and 15 mass parts of MgO-2.
・ Master chip 3
And 85 mass PA6, was prepared by kneading a 15 parts by weight of MgCO _3.
・ Master chip 4
And 85 mass PA6, was prepared by kneading a 15 parts by weight of CaCO _3.
・ Master chip 5
It was prepared by kneading 85 masses of PA6 and 15 mass parts of ZnO.

(4) Polycarboxylic acid component / EMA aqueous solution of gas barrier layer (II) forming coating solution:
EMA (weight average molecular weight 60,000) and sodium hydroxide were added to water, dissolved by heating, and cooled to room temperature. 10 mol% of EMA carboxyl groups were neutralized with sodium hydroxide, solids EMA aqueous solution of 15% by mass.
-PAA aqueous solution:
10 mol% of the carboxyl group of polyacrylic acid prepared by using polyacrylic acid (A10H manufactured by Toagosei Co., Ltd., number average molecular weight 200,000, 25% by weight aqueous solution) and sodium hydroxide is contained in sodium hydroxide. An aqueous polyacrylic acid (PAA) solution having a solid content of 15% by mass.

(5) Other resin components and PVA aqueous solution for coating liquid for forming gas barrier layer (II):
Polyvinyl alcohol (Polyal 105 manufactured by Kuraray Co., Ltd., saponification degree 98 to 99%, average polymerization degree about 500) was added to water, dissolved by heating, and then cooled to room temperature. PVA) aqueous solution.
EVOH aqueous solution:
An ethylene-vinyl alcohol copolymer (EVOH) aqueous solution having a solid content of 10% by mass, in which an ethylene-vinyl alcohol copolymer (Exeval AQ-4105 manufactured by Kuraray Co., Ltd.) is dissolved.
・ PAM:
Polyacrylamide (manufactured by Kishida Chemical Co., Ltd., reagent, weight average molecular weight 9 million to 10 million, degree of polymerization 1270 to 141,000).

Example 1
Nylon 6 resin and master chip 1 were mixed so that the magnesium oxide content was 0.5 parts by mass. This mixture was put into an extruder A and melt-extruded at 260 ° C. On the other hand, nylon 6 resin was charged into Extruder B and melt extruded at 260 ° C.
Two types of resins melted in the extruder A and the extruder B are overlapped in a die, and a sheet having a two-layer structure of a metal-containing layer (M) / resin layer (R) is extruded from a T die, and a surface temperature of 20 An unstretched multi-layer film having a thickness of 150 μm, which is (M) / (R) = 20/130 μm, was obtained by closely adhering to a cooling roll at ° C. The obtained unstretched multilayer film was sent to a 50 ° C. hot water tank and subjected to water immersion treatment for 2 minutes.
Next, an EMA aqueous solution and a PVA aqueous solution are mixed so that the mass ratio (solid content) of PVA and EMA is 50/50, and a coating solution for forming a gas barrier layer (II) having a solid content of 10% by mass. Got. This coating solution was applied to the surface of the metal-containing layer (M) of the unstretched multilayer film that had been subjected to water immersion treatment, and then dried.
The end of the film was held by a clip of a tenter simultaneous biaxial stretching machine, and stretched at 180 ° C. to MD and TD by 3.3 times. Then, the relaxation rate of TD was set to 5%, heat treatment was performed at 210 ° C. for 4 seconds, and the mixture was gradually cooled to room temperature. From the metal-containing layer (M) having a thickness of 2 μm and the resin layer (R) having a thickness of 13 μm A gas barrier laminate obtained by laminating a gas barrier layer (II) having a thickness of 0.3 μm on a metal-containing layer (M) of a plastic substrate (I) having a thickness of 15 μm was obtained.
Next, water-based ink (Aqua Ecole white ink manufactured by Toyo Ink Manufacturing Co., Ltd.) was applied to the gas barrier layer (II) of the gas barrier laminate. 4 was printed and dried with a hot air dryer at 90 ° C. for 30 seconds to obtain a gas barrier laminate having a printing ink layer. A laminate adhesive layer (III) is formed on a gas barrier laminate having a printing ink layer (Dick Dry LX-401A / SP-60 = 1/1 manufactured by DIC is used by a dry laminator so as to have a dry film thickness of 3 μm. After applying and forming), the adhesive layer (III) and the heat seal layer (IV) (LLDPE-50 μm: TUX-FCS manufactured by Tosero Co., Ltd.) are bonded together and cured at 40 ° C. for 3 days to form the adhesive layer (III). Cured to obtain a laminate in which (I) / (II) / printing ink layer / (III) / (IV) were laminated in this order. The results of measuring the laminate strength of this laminate are shown in Table 1.

Example 2
In the same manner as in Example 1, a gas barrier laminate was obtained. Next, a laminate adhesive layer (III) is formed on the gas barrier layer (II) of the gas barrier laminate (Dick Dry LX-401A / SP-60 = 1/1 manufactured by DIC is dried to a dry film thickness of 3 μm. After forming by applying with a laminator, the adhesive layer (III) and the heat seal layer (IV) (LLDPE-50 μm: TUX-FCS manufactured by Tosero Co., Ltd.) are bonded together and cured at 40 ° C. for 3 days to form the adhesive layer (III ) Was cured to obtain a laminate in the order of (I) / (II) / (III) / (IV).

Examples 3-11, Comparative Examples 1-4
Extruders A and B are mixed so that the nylon 6 resin and master chips 1 and 3 to 5 are mixed so as to have the composition shown in Table 1, and the thickness after stretching becomes the thickness shown in Table 3. An unstretched multilayer film was obtained in the same manner as in Example 1 except that the extrusion amount was changed, and was subjected to water immersion treatment.
In addition, in Example 5, it was made to be the same as that of Example 1 except having used the masterbatch 2 using the magnesium oxide from which an average particle diameter differs from the master chip 1. FIG.
Next, for other resins such as PVA and polycarboxylic acids, the gas barrier layer (II) was formed in the same manner as in Example 1 except that the mass ratio (solid content) was as shown in Table 1. A coating solution was prepared.
Using the obtained coating solution, it was applied to an unstretched film, dried and then simultaneously biaxially stretched in the same manner as in Example 1, except that the thickness after stretching was as shown in Table 1. Thus, a gas barrier laminate was obtained.
In Example 8, the polyethylene terephthalate resin (PET) was used as the thermoplastic resin, and the conditions were further changed as follows. That is, an unstretched film was produced at a cylinder temperature of 280 ° C., and the obtained unstretched film was not subjected to water immersion treatment. Moreover, the temperature in simultaneous biaxial stretching was 90 degreeC, and the temperature of heat processing was 230 degreeC.
Using the obtained gas barrier laminate, a laminate was obtained in the same manner as in Example 2 in the order of (I) / (II) / (III) / (IV).

  Table 1 shows the measurement results of the structures, oxygen permeability, and laminate strength of the gas barrier laminates obtained in Examples and Comparative Examples.

In Examples 1 to 11, gas barrier laminates excellent in laminate strength and gas barrier properties were obtained. In any observation of the peeling interface, no delamination occurred in the multilayer film constituting the plastic substrate (I).
In Comparative Examples 1 and 3, since the metal compound contained in the metal-containing layer (M) of the plastic substrate (I) exceeded 10% by mass, a gas barrier laminate having sufficient laminate strength could not be obtained. Peeling at the interface between the metal-containing layer (M) and the resin layer (R) (represented as “M / R”) and peeling within the resin layer (R) (represented as “R / R”) occur. Thus, the interlayer adhesion of the base film was not sufficient.
In Comparative Example 2, since the metal compound contained in the metal-containing layer (M) of the plastic substrate (I) was less than 0.1% by mass, a gas barrier laminate having sufficient gas barrier properties could not be obtained.
In Comparative Example 4, since the gas barrier layer (II) did not contain a polycarboxylic acid, a gas barrier laminate having sufficient gas barrier properties and laminate strength could not be obtained.

Claims (7)

The plastic substrate (I) is a multilayer film composed of a metal-containing layer and a resin layer,
The metal-containing layer contains 0.1 to 10% by mass of a metal compound , and a thermoplastic resin mixed with the metal compound is melt extruded.
Ri gas barrier layer containing a polycarboxylic acid (II) the name is laminated on the plastic substrate (I),
The gas barrier layer and the metal-containing layer are in contact,
After hydrothermal treatment at 95 ° C. for 30 minutes, the oxygen permeability in an atmosphere at 20 ° C. and a relative humidity of 65% is 0.01 to 16 ml / (m ² · day · MPa) ,
A gas barrier laminate, wherein the plastic substrate (I) is stretched . The gas barrier laminate according to claim 1, wherein the thermoplastic resin constituting the plastic substrate (I) is a polyamide resin or a polyester resin. The gas barrier layered product according to claim 1, wherein the gas barrier layer (II) contains a polyalcohol. The gas barrier laminate according to any one of claims 1 to 3, wherein the metal constituting the metal compound is one selected from magnesium, calcium, and zinc. The gas barrier laminate according to any one of claims 1 to 3, wherein the metal compound is magnesium oxide. On the gas barrier layer (II) of the gas barrier laminate according to any one of claims 1 to 5, when the laminate adhesive layer (III) and the heat seal layer (IV) are laminated in this order to form a laminate, A gas barrier laminate having a laminate strength (X) of 300 g / 15 mm or more. A packaging bag comprising the gas barrier laminate according to any one of claims 1 to 6.